REFEREE Wayne Barnes has called for patience as new scrum laws that have attracted criticism before the season has even started are trialled in the northern hemisphere.

The adjusted rules force opposing props to bind fully onto each other before engagement and the scrum will only be active when the ball is fed, which scrum-halves must now do straight down the tunnel.

While the initial focus of the laws was to enhance player welfare, their introduction has been given the added importance of overhauling an area of the game that was being significantly undermined by repeated resets.

Leicester director of rugby Richard Cockerill has been the most outspoken critic of the changes, asking why they were devised without consulting English Premiership coaches, questioning their safety and suggesting they have only served to create a different type of “mess”.

Barnes has been visiting Premiership clubs throughout pre-season to assist them in implementing the rules and insists that the general reaction has been positive ahead of the start of league competition on Friday night.

The referee said: “There has to be buy-in from everyone for this to work and what’s been good is that we’ve gone into clubs and there seems to be a will among players and coaches to make this work.

“Obviously there will be teething problems and I’m sure we’ll see that this weekend when the season starts. But we have to make sure this works so that we get better scrums and outcomes.

“The changes are going to give us different challenges. Last year it was about being accurate over who collapsed the scrum.

“But with these scrums now being closer together and the bind happening before engagement, we should see things before the ball comes in, so we can look at different things.”

The International Rugby Board (IRB) commissioned research overseen by their scrum steering group costing £500,000 that examined all levels of the game from international to youth rugby.

The results were the same at every level. By having players bind before they engage, the force of the two packs coming together – known as ‘the hit’ – is reduced by 25 per cent.

The referee then waits until the set-piece is stable before instructing the scrum-half to put the ball into the scrum straight with a call of ’yes nine’, at which point the packs can push.

Former England hooker Brian Moore has described the changes as “our last chance to save the scrum” while IRB rugby committee chairman John Jeffrey views them as a “seminal moment” in the development of the sport.

It is feared the early rounds of the Premiership and Pro12 could be marred by a succession of free-kicks and penalties as teams get to grips with the laws.

Barnes did little to refute this by warning that referees will adopt a zero-tolerance policy from the start.

“If a player continues to do something that we told them in pre-season they shouldn’t, there have to be sanctions,” he said.

“This is a season-long trial. We don’t want to start off week one being very harsh, then by week 20 everyone’s forgotten about it. We have to hold (people) to account throughout the season to make sure this works.”

“That’s why it’s important that we’ve gone into clubs beforehand, and we’ve done over 40 visits to the 12 teams.

He added: “I’m optimistic this will work. What we’ve seen in pre-season is that scrums are up, scrums are off the floor and they’re good pushing competitions. As rugby fans we all want scrums to work.”